Not guaranteed — but statistically likely for larger orders. If price moves strongly in one direction during your TWAP window (e.g. BTC dumps 3% over 30 minutes while you’re buying), the later slices fill at lower prices and you’ll get a better average than if you’d bought it all upfront. If BTC pumps 3% during your window, your later slices fill higher and you’d have been better off with a single market order at the start. TWAP reduces variance in your entry price rather than guaranteeing improvement — which is exactly what it’s designed to do. For large orders, less variance in entry price usually means less risk overall.

Yes — you can cancel a TWAP at any time from the Open Orders panel. Any slices that have already executed remain as part of your position; only the remaining unexecuted slices are cancelled. So if 3 of 7 slices have filled when you cancel, you’ll hold a position 3/7ths the size you originally intended. This is particularly useful if news breaks mid-TWAP or if price action changes your view on the trade — you can stop execution and manage the partial position you already have.

Hyperliquid’s TWAP executes each slice as a market order at the time interval — taking whatever the best available price is at that moment. This means each slice pays the taker fee (0.045%). Unlike a manual strategy where you might place limit orders for each slice to earn the maker rebate (−0.01%), TWAP prioritises execution certainty over fee optimisation. For most TWAP use cases — large positions where slippage reduction is the goal — the small fee premium over a limit-order approach is easily outweighed by the time savings and automation benefit. If fee efficiency is your primary concern on a smaller order, a series of manual limit orders may be more appropriate.